Larger diameter punches and dies designed to pierce heavier gage ferrous materials require a draw stud of sufficient diameter to withstand the tensile and bending forces imposed, the draw stud being that member which pulls the punch through the material toward and in cooperation with the die. A typical operation to pierce a 2-inch conduit hole would require the following steps. First, a pilot hole is drilled in the material to accept a draw stud of a first punch and die set. The first punch and die set is assembled relative to the material and a first hole is punched therein of a size (small diameter) to accept a larger draw stud of a second punch and die set. Then, the second punch and die set is assembled relative to the material with the larger diameter draw stud in the first punched hole. The second punch and die set punches the final 2-inch diameter conduit hole.
Although lighter gage and non-ferrous materials require less punching force than heavy gage ferrous materials, the same procedure was followed in the past to punch the same size hole therein.